linux/drivers/misc/sgi-xp/xp_main.c
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   1/*
   2 * This file is subject to the terms and conditions of the GNU General Public
   3 * License.  See the file "COPYING" in the main directory of this archive
   4 * for more details.
   5 *
   6 * (C) Copyright 2020 Hewlett Packard Enterprise Development LP
   7 * Copyright (c) 2004-2008 Silicon Graphics, Inc.  All Rights Reserved.
   8 */
   9
  10/*
  11 * Cross Partition (XP) base.
  12 *
  13 *      XP provides a base from which its users can interact
  14 *      with XPC, yet not be dependent on XPC.
  15 *
  16 */
  17
  18#include <linux/module.h>
  19#include <linux/device.h>
  20#include "xp.h"
  21
  22/* define the XP debug device structures to be used with dev_dbg() et al */
  23
  24static struct device_driver xp_dbg_name = {
  25        .name = "xp"
  26};
  27
  28static struct device xp_dbg_subname = {
  29        .init_name = "",                /* set to "" */
  30        .driver = &xp_dbg_name
  31};
  32
  33struct device *xp = &xp_dbg_subname;
  34
  35/* max #of partitions possible */
  36short xp_max_npartitions;
  37EXPORT_SYMBOL_GPL(xp_max_npartitions);
  38
  39short xp_partition_id;
  40EXPORT_SYMBOL_GPL(xp_partition_id);
  41
  42u8 xp_region_size;
  43EXPORT_SYMBOL_GPL(xp_region_size);
  44
  45unsigned long (*xp_pa) (void *addr);
  46EXPORT_SYMBOL_GPL(xp_pa);
  47
  48unsigned long (*xp_socket_pa) (unsigned long gpa);
  49EXPORT_SYMBOL_GPL(xp_socket_pa);
  50
  51enum xp_retval (*xp_remote_memcpy) (unsigned long dst_gpa,
  52                                    const unsigned long src_gpa, size_t len);
  53EXPORT_SYMBOL_GPL(xp_remote_memcpy);
  54
  55int (*xp_cpu_to_nasid) (int cpuid);
  56EXPORT_SYMBOL_GPL(xp_cpu_to_nasid);
  57
  58enum xp_retval (*xp_expand_memprotect) (unsigned long phys_addr,
  59                                        unsigned long size);
  60EXPORT_SYMBOL_GPL(xp_expand_memprotect);
  61enum xp_retval (*xp_restrict_memprotect) (unsigned long phys_addr,
  62                                          unsigned long size);
  63EXPORT_SYMBOL_GPL(xp_restrict_memprotect);
  64
  65/*
  66 * xpc_registrations[] keeps track of xpc_connect()'s done by the kernel-level
  67 * users of XPC.
  68 */
  69struct xpc_registration xpc_registrations[XPC_MAX_NCHANNELS];
  70EXPORT_SYMBOL_GPL(xpc_registrations);
  71
  72/*
  73 * Initialize the XPC interface to NULL to indicate that XPC isn't loaded.
  74 */
  75struct xpc_interface xpc_interface = { };
  76EXPORT_SYMBOL_GPL(xpc_interface);
  77
  78/*
  79 * XPC calls this when it (the XPC module) has been loaded.
  80 */
  81void
  82xpc_set_interface(void (*connect) (int),
  83                  void (*disconnect) (int),
  84                  enum xp_retval (*send) (short, int, u32, void *, u16),
  85                  enum xp_retval (*send_notify) (short, int, u32, void *, u16,
  86                                                  xpc_notify_func, void *),
  87                  void (*received) (short, int, void *),
  88                  enum xp_retval (*partid_to_nasids) (short, void *))
  89{
  90        xpc_interface.connect = connect;
  91        xpc_interface.disconnect = disconnect;
  92        xpc_interface.send = send;
  93        xpc_interface.send_notify = send_notify;
  94        xpc_interface.received = received;
  95        xpc_interface.partid_to_nasids = partid_to_nasids;
  96}
  97EXPORT_SYMBOL_GPL(xpc_set_interface);
  98
  99/*
 100 * XPC calls this when it (the XPC module) is being unloaded.
 101 */
 102void
 103xpc_clear_interface(void)
 104{
 105        memset(&xpc_interface, 0, sizeof(xpc_interface));
 106}
 107EXPORT_SYMBOL_GPL(xpc_clear_interface);
 108
 109/*
 110 * Register for automatic establishment of a channel connection whenever
 111 * a partition comes up.
 112 *
 113 * Arguments:
 114 *
 115 *      ch_number - channel # to register for connection.
 116 *      func - function to call for asynchronous notification of channel
 117 *             state changes (i.e., connection, disconnection, error) and
 118 *             the arrival of incoming messages.
 119 *      key - pointer to optional user-defined value that gets passed back
 120 *            to the user on any callouts made to func.
 121 *      payload_size - size in bytes of the XPC message's payload area which
 122 *                     contains a user-defined message. The user should make
 123 *                     this large enough to hold their largest message.
 124 *      nentries - max #of XPC message entries a message queue can contain.
 125 *                 The actual number, which is determined when a connection
 126 *                 is established and may be less then requested, will be
 127 *                 passed to the user via the xpConnected callout.
 128 *      assigned_limit - max number of kthreads allowed to be processing
 129 *                       messages (per connection) at any given instant.
 130 *      idle_limit - max number of kthreads allowed to be idle at any given
 131 *                   instant.
 132 */
 133enum xp_retval
 134xpc_connect(int ch_number, xpc_channel_func func, void *key, u16 payload_size,
 135            u16 nentries, u32 assigned_limit, u32 idle_limit)
 136{
 137        struct xpc_registration *registration;
 138
 139        DBUG_ON(ch_number < 0 || ch_number >= XPC_MAX_NCHANNELS);
 140        DBUG_ON(payload_size == 0 || nentries == 0);
 141        DBUG_ON(func == NULL);
 142        DBUG_ON(assigned_limit == 0 || idle_limit > assigned_limit);
 143
 144        if (XPC_MSG_SIZE(payload_size) > XPC_MSG_MAX_SIZE)
 145                return xpPayloadTooBig;
 146
 147        registration = &xpc_registrations[ch_number];
 148
 149        if (mutex_lock_interruptible(&registration->mutex) != 0)
 150                return xpInterrupted;
 151
 152        /* if XPC_CHANNEL_REGISTERED(ch_number) */
 153        if (registration->func != NULL) {
 154                mutex_unlock(&registration->mutex);
 155                return xpAlreadyRegistered;
 156        }
 157
 158        /* register the channel for connection */
 159        registration->entry_size = XPC_MSG_SIZE(payload_size);
 160        registration->nentries = nentries;
 161        registration->assigned_limit = assigned_limit;
 162        registration->idle_limit = idle_limit;
 163        registration->key = key;
 164        registration->func = func;
 165
 166        mutex_unlock(&registration->mutex);
 167
 168        if (xpc_interface.connect)
 169                xpc_interface.connect(ch_number);
 170
 171        return xpSuccess;
 172}
 173EXPORT_SYMBOL_GPL(xpc_connect);
 174
 175/*
 176 * Remove the registration for automatic connection of the specified channel
 177 * when a partition comes up.
 178 *
 179 * Before returning this xpc_disconnect() will wait for all connections on the
 180 * specified channel have been closed/torndown. So the caller can be assured
 181 * that they will not be receiving any more callouts from XPC to their
 182 * function registered via xpc_connect().
 183 *
 184 * Arguments:
 185 *
 186 *      ch_number - channel # to unregister.
 187 */
 188void
 189xpc_disconnect(int ch_number)
 190{
 191        struct xpc_registration *registration;
 192
 193        DBUG_ON(ch_number < 0 || ch_number >= XPC_MAX_NCHANNELS);
 194
 195        registration = &xpc_registrations[ch_number];
 196
 197        /*
 198         * We've decided not to make this a down_interruptible(), since we
 199         * figured XPC's users will just turn around and call xpc_disconnect()
 200         * again anyways, so we might as well wait, if need be.
 201         */
 202        mutex_lock(&registration->mutex);
 203
 204        /* if !XPC_CHANNEL_REGISTERED(ch_number) */
 205        if (registration->func == NULL) {
 206                mutex_unlock(&registration->mutex);
 207                return;
 208        }
 209
 210        /* remove the connection registration for the specified channel */
 211        registration->func = NULL;
 212        registration->key = NULL;
 213        registration->nentries = 0;
 214        registration->entry_size = 0;
 215        registration->assigned_limit = 0;
 216        registration->idle_limit = 0;
 217
 218        if (xpc_interface.disconnect)
 219                xpc_interface.disconnect(ch_number);
 220
 221        mutex_unlock(&registration->mutex);
 222
 223        return;
 224}
 225EXPORT_SYMBOL_GPL(xpc_disconnect);
 226
 227static int __init
 228xp_init(void)
 229{
 230        enum xp_retval ret;
 231        int ch_number;
 232
 233        /* initialize the connection registration mutex */
 234        for (ch_number = 0; ch_number < XPC_MAX_NCHANNELS; ch_number++)
 235                mutex_init(&xpc_registrations[ch_number].mutex);
 236
 237        if (is_uv_system())
 238                ret = xp_init_uv();
 239        else
 240                ret = 0;
 241
 242        if (ret != xpSuccess)
 243                return ret;
 244
 245        return 0;
 246}
 247
 248module_init(xp_init);
 249
 250static void __exit
 251xp_exit(void)
 252{
 253        if (is_uv_system())
 254                xp_exit_uv();
 255}
 256
 257module_exit(xp_exit);
 258
 259MODULE_AUTHOR("Silicon Graphics, Inc.");
 260MODULE_DESCRIPTION("Cross Partition (XP) base");
 261MODULE_LICENSE("GPL");
 262